<!DOCTYPE html>

<head>
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <script src="vue.3.2.37.js"></script>
</head>

<body>
  <div id="app">

    <test-c></test-c>

    <test-a></test-a>
  </div>
  <!-- 
 
 -->

</body>
<script>
  const { createApp, ref, reactive, watch, computed } = Vue
  const app = {
    setup() {
      // 入口函数
      return {
      }
    }
  }
  const vm = createApp(app)
  // 组件在mount 前 注册
  vm.component('testC', {
    template: '<div>hello C</div> <input />'
  })
  vm.component('testA', {
    template: '<div>hello A</div> <input />'
  })
  vm.mount('#app')
</script>

</html>